Is your child consuming too much caffeine without you even knowing it? The answer may be yes. The Food and Drug Administration (FDA) says 100-200 milligrams (mg) a day is safe, but a recent study published in the journal Pediatrics found even low doses (under 100 mg) of caffeine can have an effect on your child's heart rate and blood pressure. These low doses, the equivalent of a cup of coffee or half to a full can of soda, were found to slow children's heart rates and raise blood pressure in all ages, and have an ever bigger effect after puberty, most notably in teen boys. Caffeine can also cause difficulty sleeping and concentrating, and other ailments like nervousness, headaches, and an upset stomach. The FDA doesn't require manufacturers to list caffeine content on food labels, so be aware of where caffeine may be lurking.